1. Field of the Invention
This invention relates generally to a method by which broadcast programs can be edited after transmission and more particularly to an improved method for accomplishing the recognition and categorization of program segments and for causing the editing of program material to occur upon recognition of material categorized as unwanted.
The term "program" as used herein is defined in the generic sense and may include the complete content or any individual segment or segments of any type of program identity, such as entertainment broadcasts, commercials, news programs skits or the like, which are broadcast via television or radio. There are many needs for field editing such programs, such as in the removal of commercial announcement segments from news or entertainment programs, either upon initial reception or when taping to preserve such programs for subsequent viewing and/or listening. Another need is for blocking the receipt of programs or segments deemed to contain objectionable content, as in preventing children from watching and/or listening to (henceforth for simplicity, referred to as "monitoring") inappropriate programming.
2. Description of the Prior Art
A previous method and system for the editing of broadcast programs after transmission is disclosed in a previous invention by this applicant (U.S. Pat. No. 4,420,769) wherein automatic recognition of unwanted program material is accomplished by a system which analyzes the program content of broadcast signals in such a way that that program content is caused to supply its own essentially unique code or signature. This code is compared to codes previously programmed, by storage in one or more memories, as representing material to be edited, and when it is found that the code generated matches or substantially matches a previously stored code, editing is caused to occur. This code or signature is also commonly referred to as a "data set", "data bit representing a digital word", "feature set" or "program code", terms which are to be considered as equivalent and which are used interchangeably in this application.
One fundamental problem associated with this approach is the massive amount of data processing which can be required to establish a reasonably reliable signature.
Attempts at reducing the amount of data processing necessary in establishing a signature have been explored in previous inventive attempts, but not to unimproveable degrees.
Consider for example the teaching of U.S. Pat. No. 4,230,990 (Lert, Jr. et al) in which the need for continuously sampling and then generating a signature for each minute segment of broadcast is reduced. In that invention a signature is generated only upon detection of certain cue signals which are broadcast, primarily, in addition to the informational content of the program. The problem inherent in applying the teaching of that patent to field editing is that its use depends upon consistency in the format in which broadcasts are assembled, i.e., the broadcasts contain the existence of dead air between programs, a certain specific program logo be broadcast, or that programs contain a voluntarily superimposed code. However, none of these cues are inherently necessary in any particular broadcast. Obviously, as broadcasters may or may not find the field editing of their program content beneficial to their particular interest, no reliance can be made on the existence of any particular element of broadcast transmission not essential to the informational content of the broadcast program.
Another aspect of the applicant's previous invention (U.S. Pat. No. 4,420,769) is that generation of and programming the digital words associated with unwanted program material occurs concurrently with initial receipt of such material. A useful improvement, therefore, would be the providing of one or more means for programming the device for editing all unwanted material, including first transmissions thereof.
A further aspect of the applicant's previous invention is that program material is discussed as having been transmitted in analog form. Such signals, however, are inherently subject to degradation from outside interference and decayof signal strength, whereas transmissions in digital form are not. It is expected, therefore, that at some time in the future, broadcasters will replace the current analog format with a digital transmission.
A further useful improvement, therefore, would be simplified capability for processing digitally transmitted signals.